Perforator knife



Jan. 19, 1932. D. sHULL PERFORATOR KNIFE 2 Sheets-Sheet 1 Filed Nov. 2l,1928 mmw hu//////%//%/////% a 4 5 7 @ov HW/4 .f M 5,37 www ,5

Jan. 19, 1932.

` D. 1 SHULL PERFORATOR KNIFE Filed' Nov. 2l, A.1928 2 SheetS-Shet 2 M5,. Y m5. F "wlw @a @sm s 1v, .4 //,II\\*W,

Patented Jan. 19, 1932 STATES' PATENT BANIEL L. SHULLOF ONG` BEACH,CALIFORNIA rnitronnroii KNIFEv l Appiieation filed November 2l, 1928.SeraiNo. 320,939.l

My invention relates to oilwell equipment and vmore particularly tocasing perforators and is an improvement on my prior invention,application entitled Double casing perforator, No.256,178,-led February'23, 1928.

After A a well has been drilled, f a casing called the water string isinserted therein, and there is Vextended in this water string a l casinglrnown as the oil spring. The oil Aio string is provided with `a screenpipe which extends through the oil sands'andv the screen pipe is adaptedfor the purpose of straining from the inward seeping oil gravel and sandwhich might injure the oil pump. The screen pipe is either formed priorto the installation of the oil-'string or else the oil string isperforated at the levelof the oil sands after installation by aperforator provided for this .2 purpose. It is sometimes desirable toperforate the waterk string also,l as when the latter has been cementedoff below the oil bearing strata which itis desired to drain,.and`it isinconvenient or impossible to raise the lower end of the water stringtothis strata.

' It is an object of myinventionto provide a novel casing perforatoradapted to perforate one or morecasings, and likewise, thecementaroundthe water string before i communication is established between theoil string andthe oil bearing strata.

Since those perforators now in use are not adapted to givethe operator apositive indication of the completion of the perforation, the operationoftentimes continues until perforations are in the form of long slitswhich materially weaken the casing and decreases the efficiency of thestraining action.

it' is another object of my invention to pro- 1- vide a perforator ofthe class described which will give aV positive indication to theoperator when the casings have been perforated.

in the casing perforator shown in mypapplication Serial No. 256,178,referred to heretofore, much trouble is had with the breaking of thecutter blade of the perforator. When the blade is forced into the casingto be cut,

it is moved outward'and tends to pivot around the upper gripping portionwhich engages the casing. Y Since the blade is iny clined upward andinward the upper face of casing.

the

f the blade engages the upper edge of the slot beingrformed. At thistime thereis a down force on the blade where it engages the upper edgeof the slot, tending to move the blade downward, but this downwardmovement' is resisted by the engagement of the gripping portion and thecasing.` kEither of two actions will occur-fthe casing will be torn atthe upper end of the slot being formed or thejblade will break. Myexperience has been` Vthat thel blade will break after a few slots havebeen cut. y n

, It is one of the important objects of my inventionV to provide y acasing perforator in whichY thei cutter is free to move vertically; thatis, to move along the casing as the blade yis forcedthroughthe casingsothat the cutter maybe moved or guided'by the blade in order thatshearing strains in the blade will .1...

be eliminated.`

' A still further object of my invention is to provide a casingperforator in which the cutter engages the casing adjacent lthe placewhererthe blade thereof is cutting lthe slot,

and in which friction reducing means is pro- Y vided at .the rengagementpoint of the cutter and the casing, so that the cutter is free to moveup or down as the blade is being forced outward or moved inward relativeto the A still further object `ofmy invention is to provide frictionreducingmeans in the form of roller means.

it :is a further object of my` invention to provide a casing perforatorwith a cutting member having friction reducing'means Vso lustrated bythe accompanying drawings, in which:

Fig. 1 is an enlarged vertical section of the perforator of my inventionwith the cutter member in retracted position.

Fig. 2 is a vertical section similar to Fig. 1, except that the cuttermember is released and in cutting position.

Fig. 3 is an enlarged cross-sectional view indicated by line 3 3 of Fig.1.

Fig. 4 is a vertical section of part of the body portion of myperforator showing the position of the cutter at the completion of theperforation.

Fig. 5 is a detailed enlarged perspective view of my perforator cutterdetached from its operative mechanism.

F ig. 6 is a fragmentary view of Fig. 1, showing an alternative type ofcutter with one large guide roller and showing two different positionsof the cutter element.

Fig. 7 is a fragmentary sectional view showing the lock means providedon the cutter actuating device.

Referring to the drawings and particularly to Fig. 1, an outer casing orwater string 10 has been inserted in a well and is cemented off at itslower end in the usual manner. The upper end of the casing 10 isprovided with a casing head not illustrated, forming a tight fit betweenthe water string 10 and an oil string 11 which is extended inside thewater string. Vhen it is desired to permit oil4 to flow into the oilstring 11 at a level above that at which the water string is cementedoff, as at an oil stratum, a perforator 12 of my invention is attachedto the lower end of a jar and lowered on a cable through the oil string11 in the ordinary manner. The jar and weight mechanism connectedtherewith may be of the conventional type known in the art, comprisingtwo interlocking links with a ram or weigh attached to the upier link.

The perforator 12 includes a body 13 cylindrical in cross-section, asillustrated in Fig. 3 with a coupling 14 at its upper end adapted tothreadedly receive the lower end of a link of the jar mechanism notillustrated. T he lower end of the body 13 has a cylindrical hub 15 oflesser diameter than the body 13, and this hub is provided with externalthreads 16 for a purpose to be described later.

Formed diametrically in the body 13 and with its axis parallel to theaxis of the perforator 12 is a cutter slot 17 having a vertical, aninclined, and an arcuate wall, as indicated by the numerals 18, 19, and20 respectively in Figs. 1, 2, 4, and 6. At right angles to the cutterslot 17 a cam slot 21 ex tends through the body 13, this cam slotcomprising a portion 22 and a portion 23 substantially parallel to thevertical wall 18 and the inclined portion 19 of the cutter slot 17.

Positioned in the cutter slot 17 a cutter element 24 non-rotatablymounted on a cutter shaft 25 slidably disposed in the cam slot 21, thecutter shaft 25 being of a length which prohibits its projection outsidethe body 13 at any position in the cam slot 21 for obvious reasons. Thecutter element comprises a rectangular body portion 26 and a blade 27disposed at approximately right angles to the body portion. The blade 27is provided with a lower edge 28 and a forwardly curved cutting edge 29forming a continuation of the edge 28. T he cutter elementen bloc ispreferably forged from relatively hard metal and the body portionthereof is provided with flat sides 30 and 31 and fiat edges 32 and 33.The blade 27 is centrally disposed on the edge 3 at the lower end andthereby forms with the body 26 the shoulders 34 t the opposite sides ofsaid blade. A flange 35 is centrally disposed on the edge 32 of the bodyportion 26 and forms with the said body the oppositely disposedshoulders 3G. The shoulders 36 adacent the base of the cutter bodydiverge inwardly towards the shoulders 34 and form a stop 37. The flange35 extends from a point adjacent the upper end of the edge 32 of thebody portion and dually tapers outwardly and increases in thicknesstowards the lower end of the body portion as at 38 and then in ".Jardly,the lowerA surface thereof merging into the lower edge 28 of the blade27.

The upper end of the body portion of the cutter element 24 is bifurcatedfor the reception of upper and lower friction rollers 39 and 40, theupper rollers 39 being mounted on a stub shaft 41 having bearings inbosses 42 formed on the outer edge portions of the bifurcations 43 and44, while the lower friction roller 40 is mounted below but in advanceof the roller 39 on a stub shaft 45 having bearings in the bifurcations43 and 44. Resultant of mountingl the upper roller 39 in the bosses 42,the same is projected forwardly of t-he flange 35 and upwardly from thebifurcations 43 and 44. The roller 4() projects outwardly from thebifurcated portions 43 and 44 on the edge 33 and is adapted forengagement with the inner surface of the casing 11.

rlhe cutter element 24 is so mounted on the cutter shaft 25 as to permitthe flange 35 to fit within a groove 46, Figs. 3 and 4, formed in therear wall of the cutter slot 17 and the shoulders 33 of the cutter toslide upon the eppositely disposed Ishoulders 47 formed resultant of theplacement of said groove 46.

The external threads 16 of the cylindrical hub 15 are adapted to screwinto internal threads of a hollow cylindrical sleeve 48 of a trip cage49. Threadedly secured in the lower end of the sleeve 48 is an end plate50 with a central cylindrical bore 51 through which a trip shaft 52 isadapted to slidably extend.

Retained in threaded engagement with the upper end of the trip shaft 52as by a lock nut V cylindrical bore 56 in the body-13 of the cutjso 'lows ter 12 which communicates with the cutter slot 17, is anoperatingpin 55. The operating pin 55fis provided with a hub 57 at itslower end head S at its upper end, both of which are of greaterdiameterthan the bore 56 so that the movement -of the l:pin in the boreis limited. l Y

Referring particularly to Figs. land 7, the trip plate 54 carries a pin75 which projects outward into a slot 7 6 carried bythe tube 48. Theupper end of the slot which is indicated by the numeral 7 7 is solocated that when the pin 75 rests in the slot the trip plate 54is'prevented form moving upward in the yLube 4 and consequently cannotmove the operating pin upward. The lower end of the slot 76 is open at78 and-below the slot is an in,- clined wall 79. When, the trip plate 54is moved downward tothe bottom end of the slot 7 6 the pin 75 willengage the inclinedwall 79, thus causing the trip plate to rotaterelative to the tube 43. This willmove the pin fromthe lower end of theslot 78 so that when the body 12 is subsequently lowered the pin 7 5will notprevent the trip plate 54 from moving upward into the positionshown in Fig. 2. in which position the operating pin 55 is elevated soas to operate the perforator cutter. e

rlhreadedly secured to the lower end of the trip shaft 52 is acylindrical stop member slidably disposed in a cylindrical sleeve- 6'0which is threadedly attached at its lower endto a spring-retaining shaft61. Disposed between the cylindrical stop member 59 and thespring-retaining shaft 61 in the cylindri' cal sleeve is a coil spring62 which acts as a shocl absorbing member fortheftrip shaft lt should beobvious that the trip shaft 52 is free to rotate relativek to thespringretaining shaft 61.. Attached as by screws 63 are flat springs 64here shown fragmen-A tary, the said springs being preferably four innumber, adapted to frictionally and re- .iliently engage the innersurface of the oil string 11. f l

rlhe operation of my invention is as fol- The cutter is placed in theposition shown inFig. 1 fand the apparatus with'its associated viar andweight is lowered by the cable into the oil string` llto the level atwhich it is i desired toperforate the casings.

lVhen the apparatus is at the level at which .it is desired to operatethe cutter, the cable is subjected to an upward pull. Because of theengagement of the fiat springs 64 with the casing` 11, this causes arelative movement between the bodv 13 and the spring-retaining shaft 61so that the spring-retaining shaft 61, the trip shaft 52, and the tripplate 54 move downwardlyrelative to the body 13. 'lJVhen the trip platemoves to the lower end of the tube 48 thepin 75 engages the inclinedwall 79, causing the trip plate and shaft 52 to rotate relative to thebody 12 and the tube43. This moves the pin from alignment with thev slot76. Then the body and associated partsare then lowered the trip plate 54is free to move upward into such a position that the operating pin 55willbe actuated. When the operating pin 55 is actuated. by raising itthe head 5S thereof engages the lower edge of the blade 27 and swingsthe cutter on its pivot so that theblade is moved into engagement withthe casing to be perforated, as shown in As the weight is raised anddropped by the cable the cutting edge 29 of the cutter blade 27 isforced into the casing 11. Each successive blow on the perforator causesthe cutter to move upward relative to the body 13 in the cam slot 21.Because of the inclined portion 23 of the cam' slot 21 this relativemovement forces the cutter blade 27 further into thecasing 11.VTheroller 40 on the cutter element engages the inner surface of thecasing 11 to retain the blade portion 27 in proper cutting posi-Jion.The pounding act1 on is continued until both casings and the vformationimmediately adjacent are l perfo- It should be noted that because of thef rated. fact that the cutter 24 is operating through a circular swing,the cutter blade has an eX- ceptionally long throw so that any cement ornon-porous formation .adjacent kto the outer casing can also beperforated.

l/Vhen the cutter blade 27 has finished the perforation, the cuttershaft 25 will be at the top of the inclined portion 23 of the cam slot21 as illustrated in Fig. k4. At this time the body 13 and j ar andweight will drop kuntil the cutter shaft 25 reaches the top of thevertical portion 22 of the cam slot 21, thus giving the operator apositive indication of the completion of the perforation.

The perforator12 is then Vpulled upward, the cutter shaft 25 slidingl inthe inclined poreoy tion 23 of the cam slot 21 and removing the fcutterblade 27 from the perforation. The frictional engagement of theflat springs 64 withthe casing 11 causes the spring-retaining shaft 61,thetrip shaft 52 and thetrip plate 54 to move downward relative to thebody 13 when the whole apparatus moves upward as a unit. f

'The downward movement` of the trip plate 54 relative to the body 13permits the operating pin 55 to assume the position shown in Fig. 1 sothat'the movement of the cutter shaft 25 in the inclinedfportion 23 ofthe cam slot 21 may continue untilthe cutter 24 assumes the positionshown in 1, in which it ofersno resistance to the-upward movement of theperforator. This upward movement of the apparatus is continued untilthat level is reached at whichanother perforation is made. The cutter 24is moved into operating position in this second location by simplylowering the weight. rl`he flat springs 64e retain the trip plate 5d inthe same position while the body 13 is lowered until the trip platecauses the operating pin to move the cutter 2- into cutting position.Thereafter trie operation is identical with that already described.

It will be noted that when the blade has been brought into engagementwith the casing to be perforated and when the body is lowered there willbe a relative vertical movement between the cutter and the body. Byreason of the inclined portion of the slot the entire cutter will bemoved outward from the body and the cutter will be so swung that theblade and the anti-friction means in the form of the roller l0 bothengage the casing. Upon furtl er downward movement of the body 13 theinclined slot 19 operating on the pin 25 exerts a force against thecutter which tends to pivot it around the anti-friction means l0. Theblade I? theref re is caused to penetrate the casing. In vies of thefact that the blade when it starts its cutting operation is inclined andis higher its inner end than at its outer end, as the blade is forcedinward, the upper face of the blade the upper wall of the slot beingformed and as the outward or cutting movement of the blade continues,this pressure becomes greater due to the fact that the blade isinclined. lfhen the pressure of the upper face of the blade against theupper wall of the slot being formed reaches a certain amount the entirecutter will move downward so that the blade may pass through the openingbeing formed without tearing the upper wall of the slot being formed,and preventing excessive shearing strains from bein@r placed on theblade. It will 'therefore be seen that the anti-friction means not onlyacts as a fulcruin for the cutter but in addition acts as a means whichpermits the critter' to move vertically anc acts as a means whichpermits the cutter to be guided by the blade as it passes through theslot being formed. lhen the casing is perforated, as shown in Fig. fl,the upper face of the blade 27 is in substantially a horizontalposition. It has reached this horizontal position not by the lowerportion or the outer portion of the upper edge when in the positionshown in Fig. l moving upward to the level of the upper portion or innerportion of the upper edge but by the cutter moving bodily downward sothat he blade 27 will pass through the perforations without tearing awaythe upper end of the perforation and without placing excessive strainson the blade which would result in a breakage. ldfhen the cutter 24 hasassumed the position illustrated in Fig. e, the roller 39 engages withand rotates on the rear wall of the groove 415 and takes up the frictionencountered by it with the body 13.

In the modification illustrated in Fig. 6,

the construction is the same as in the preferred form, with theexception, that a single relatively large roller 61a on the cut-terelement 62 takes the place of the two rollers 39 and 10. In this formthe roller 6l functions to reduce the friction by engaging at one sidethe inner surface of a casing 63a and at the other side the inner wallof a groove 64;a in the cutter slot G5. In this form the cutter element62 is likewise formed with a blade 66.

In this manner a direct long thrust is imparted to the cutter blades 27and 66. Likewise, a resultant of the use of the rollers 39, 40 and 61a,the friction which would normally be encountered between the upper partof the cutter body and the casing wall and the perforator body, is takenup by the rollers. It is likewise obvious, that resultant of the novelconstruction and mounting of thc cutter element in the perforator bodythe shearing stress on the blade member is minimized and consequentlythe shearing or breaking olf of the cutter blades is prevented.

lVhile the preferred forms of embodiment of my invention aboveillustrated and described are fully capable of fulfilling all of thepurposes primarily stated, I do not wish to be specifically limited tothem, for it is to be understood that my invention may be embodied invarious other forms, all coming within the scope of the claims whichfollow.

I claim as my invention:

1. In a casing perforator, the combination of: a body; a cutter carriedby said body and movable relative to said body, said cutter having ablade adapted to penetrate a casing, and engaging means adapted toengage s casing near the place where said blade penetrates said'casing,said engaging means permitting said cutter to move along said casingland to be guided by said blade as it moves through said casing; andoperating` means whereby said cutter is operated by said body.

2. In a casing perforator, the con'ibination of: a body; a cuttercarried by said body and movable relative to said body, said cutterhaving a blade adapted to penetrate a casing, and roller means adaptedto engage said casing near the place where said blade ocuftratcs saidcasing, said roller means permitting., said cutter to move along saidcasing and to be guided by said blade as it moves through said casing;and operating means .vhereby said cutter is operated by said body.

3. In a casing perforator, the combination of a cutter having a bladeadapted to penctrate a casing, and fulcrum means at apted to engage saidi adjacent to said blade. said fulcrum means beii p; der ned to pe mitrelative movement of id cutter alon,v casing; and inechanisi or forcingsaid cut ter outward against said casing around f id fulcrum means.,said blad-e being caixrd penetrate said casing, said fulcrum meansmoving along said casingV as said blade moves through said casino.

4. In a casing perforator, the combination of: acutter having a cutterbody, a. blade extending at an angle to said body and a fulcruin meanson said cutter body adapted to engage said casing adjacent to saidblade, said fulcruin means being designed to permit relative movement ofsaid cutter along said casing; and mechanism for forcing said cutteroutward against said casing around said fulcrum means, said blade beingcaused to penetrate said casing, said fiile-rum means moving along saidcasing as said blade moves through said casing.

5. In a casingperforator, the combination of: a cutter having a bladeadapted to penetrate a casingand roller means adapted to engage saidcasing adjacent to said blade, said roller means being designed topermit relative movement of said cutter along said casing; and mechanismfor forcing said cutter outward against said casing around said rollermeans, said blade being caused to penetrate said casing, said rollermeans moving along said casing as said blade moves through said casing.

6. In a casing perforator, the combination of: a cutter having a cutterbody, a-blade extending at an angle to said body and a roller means onsaid cutter body adapted to engage said casing adjacent to said blade,said roller Y means being designed to permit relative movement of saidcutter along said casing; and mechanism for forcing ,said cutter outwardagainst said casing around said roller means,

said blade being caused to penetrate said Vcasing, said roller meansmoving along said casinfr as said blade moves through said casing;

In a casing perforator, the combination of: a shell having a cutterreceiving cavity a cutter in said cavity, said cutter having a body anda blade extending therefrom; operating means connected to the lower partof said body and to said shell whereby said cutter is operated so thatsaid blade penetrates a casing; and friction reducing means at the upperendof. said body for engagement with the bottom of said cavity.

8. As a new article of manufacture, a cutter for a casing perforatorconsisting of a body; a blade extending from said body at an anglethereto; and means associated with said body for reducing the frictionbetween said body andthe casingjbeing perforated, said means tending tomove said blade into cutting engagement with said casino.y y

9. As a new article of manufacture, a cutterk for a'casing perforatorconsisting of: a

body; a blade extending from one end of said body at an angle thereto;and means associated with said body for reducing the friction blade intocutting engagement with said casy ing. Y

Y l0. As a new article of manufacture, a cutter for a casing perforatorconsistingk of; a body; a blade extending from said body at a rightangle thereto; and means associated with said body for reducing thefriction between said body and the casing being perforated, said meanstending to move said blade into cutting engagement with said casing.

11. As a new article of manufacture, a cutter for a casing perforatorconsisting of: a body; a blade extending from said body at ananglethereto; and a. roller associated with said body for reducing thefriction between said body and the casing being perforated, said rollertending to move said blade into cutting engagement with said casing.

InA testimony whereof, I have hereunto set my hand at Los Angeles,`California, this 15th day of November, '1928.`

` DANIEL L. SHULL.

between said body and the casing being pery Y forated, said meanstending to movesaid

